Mercruiser 3.7 heat exchanger repair

[Ugarph1982]

Hello all,

I have a1988 3.7L with a 4” heat exchanger. When I pour coolant into the reservoir, it comes out through the water inlet ports on the out drive. Obviously a leak in the heat exchanger.

I have purchased a pressure tested unit from ebay but who knows how long that will last. Has anyone had luck having radiator shops repair their units? Pretty common for them to develop internal leaks? Removing the exchanger revealed coolant in both circuits.

Thanks!
Russ

 

[Scott Danforth]

Radiator shops repair heat exchangers every dat.....its what they do

 

[stonyloam]

The raw cooling water flows through the tubes in the exchanger, and the coolant flows around the tubes. Sounds like you have a hole in one or more tubes. The bad tubes can be plugged at the ends to stop the leaks, and as long as it is only a couple of tubes it should be OK. A good radiator shop should be able to fix it.

 

[Scott Danforth]

Could also be a tube sheet to shell leak